PSAs are well known to possess certain properties at room temperature including the following: (1) aggressive and permanent tack, (2) adherence with no more than finger pressure, (3) sufficient ability to hold onto an adherend, and (4) sufficient cohesive strength to be removed cleanly from the adherend. Materials that have been found to function well as PSAs are polymers designed and formulated to exhibit the requisite viscoelastic properties resulting in a desired balance of tack, peel adhesion, and shear strength.
Petroleum-based materials such as, for example, synthetic rubbers (for example, styrene/butadiene copolymers (SBR) and styrene/isoprene/styrene (SIS) block copolymers), and various (meth)acrylate (for example, acrylate and methacrylate) copolymers) are commonly used for the preparation of PSAs. PSAs made by UV radiation polymerizing an alkyl acrylate (for example, iso-octyl acrylate), a monoethylenically unsaturated copolymerizable monomer (for example, acrylic acid, N-vinyl pyrrolidone, etc.), and poly-(α-olefins) (for example, poly(1-hexene), poly(1-hexene-co-propylene-co-ethylene, etc.) are known in the art, for example, to exhibit good high and low temperature performance and excellent adhesion to low and high energy substrates (see, for example, U.S. Pat. No. 5,202,361 (Zimmerman et al.)).
Replacing some of the petroleum-based raw materials in PSAs with renewable resources can be attractive both economically and environmentally. Renewable plant-based raw materials are relatively inexpensive, and their use can contribute to global sustainability by not depleting scarce resources. In addition, many naturally occurring materials such as plant oils are biodegradable in natural media.